Arming locking device for a fuze



Jan. 31, 1961 I c. F. BILD 2,969,737

ARMING LOCKING DEVICE FOR A FUZE Filed Jan. 25, 1952 v 2 heets-sheetl FIG.2. 1 34 INVENTOR. CHARLES F. BiLD jaw/Z4;

RMA n ATTYS- Jan. 31, 1961 Filed Jan. 23, 1952 C; F. BlLD ARMING LOCKING DEVICE FOR A FUZE 2 Sheets-Sheet 2 FIG.4.

VENTOR. CHA ES F BILD 1 Arrrs.

The present invention relates to a fuze and 'more particularly to an arming locking device for a fuze which is adapted-to prevent premature arming.

1 Heretofore, 'fuzes have been armed by centrifugal force caused by the spin of theprojectile or by means of the set back forcedue to inertia as the missile is fired from the gun or by a combination of these forces. Many of these arming devices are not adaptable to the newly developed low spinning projectiles. Furthermore such fuzes are more likely to be armed by accidental drop tha'nthe fuze presently disclosed.

The present invention may be used in many types of fuzes; It'is shown herein as used with a gas pressure operated fuze. 'A rotor is provided with a detonator which in the armed position is aligned with a primer and lead-in charge. -which engages a groove in a pressure'operated slidable "member.

This rotor is provided with a tooth Also engaging in this groove is a pin which is spring biased to a retracted position. This pin is held in the operative position by'means of an elongated-rack .member which is spring urged to an engaged position with the-pin. 'The teeth on this member are engaged by a rotatablegear. *Upon set back this elongated rack is retracted from an engaged position with the pin and,

when inthe completely Withdrawn position, enlarged (teeth on the elongated rack engage the gear, causing the invention resides in the provision of the elongated rack with enlarged teeth and theg'ear wheel which adds sufficient weight to the unlocking means to prevent the arming of the fuz'e by'accidentaldrop. It will be seen that the set 'back'fo'rcepmust be of such duration that the rack member will not only compress the spring but will'-.also overcome the inertia of the gear Wheel.

The, primary object of the present invention is the rates Patent 2,969,737 Patented Jan. 31, 1961 Ice an inoperative position and preventing reengagem'ent of the rack with the spring pressed pin.

provision of an arming device for a fuze particularly adapted for use with a low spinning projectile.

A further object of this invention is to provide an arming device for a fuze which will distinguish between the set back resulting from an accidental drop and that arming of the fuze by accidental drop.

A still further object of this invention is the provision of an arming device for a fuze having a rack with enlarged teeth as a locking means for a spring pressed pin whereby upon withdrawal of the rack member the enlarged teeth engage a gear thereby shifting the rack" to Other objects and many of the. attendant advantages of this invention will bereadilyappreciated as .the same becomes better understood by'reference'to the following detailed description when considered in connection 'with the p ying drawings wherein:

Fig. 1 is a view of the fuze innelevation;

Fig. 2 is an enlarge'd-s'ectionalview taken along the line 2-2 of Fig. 1;

Fig. 3 is a sectional viewataken along the-line- 3-3 of Fig. 2;

Fig. 4 is a view-similarrto'Fig; 2- showingthe. fuze in armed position;

Fig. 5 is a sectional view taken: along the:line5- --5.of Fig.4; and

Fig. 6 isa sectional view taken along the line 6-. 6 of Fig. 5.

Referring nowv particularly to; Fig. 1 there is shownxa fuze composed of sections 1, 2, 3 and 4 whichare detachably secured together in any suitable manner as, forexample, by means-ofstuds 5 .and'6' (Fig. 2). press fitted in cover plate 1, center sections2 an'd 3, and lower .section 4.

Withinlower section 4 there-is, provided a bore 7 having a screw threaded cap '-8?whichx'may be removed in order to insert slidable plungeri'9. :Thiscplunger isrprovided'with a flaredz end'portion'. 11 which seats-in asimilarly flared portion inzbore" 7. The-oppositeend portion of plunger'9'is provided withzaicentral screw threaded aperture .to receive a threaded iendssection 12'havinge'a circumferential groove 13.

Within lower section I 4 of the x'fuzebody' :is' further provided aycircular' recess 14 within which isro'tatably mounted on shaft-.15. a rotor: 16having a'por-tionthereof cutaway as at'17 and a tooth 18 whic-his adapted tobe received withinwgroovef131of end section 12. Rotor 16 is further provided witha chamfereds'ection on the lower surface'thereof at Hand a: port 21. Port 21-is adapted to receive a-detonator'whi'ch in the armedposition ofithe rotoi'is aligned with a. lead-in charge locatedwithina port 22 in the bottom section 4 beneath rotor 16 and a primer (not shown) which is located in sections in alignment with port 22. Within recess '14 is fixedly mounted a stop pin: 23"which limits the rotational movementof rotor 16. 'A spring 24 suitably securedin section 4 of the fuze body' is. adapted to enact with a notched portion 25 of the rotor to retain the rotor inthearrhd position.

. any suitable: means such: as 1 an 'inertia switch lo'cafe'd'in a port 28. The details of construction of the gas generating device and actuating means therefor form no-part of the present invention and may be of'any Well known variety. For. example in the application' of -Robert"O. Wynn' for a Combination Fuz'e fora l3orrib,.S eria'I No. 748,328, filed May 15, 1947, now Patent No. 2754,760, is disclosed a gas genefating' deviee and detonator therefor which could be adapted for use in the' present invention. I

Located within section 4'of the fuze body is a bore 29 in which is provided a headed locking pin 31. This bore communicates with bore'7 through a reduced. aperture 32. The locking pin 31 is adapted to engage groove 13 in head portion 12 of punger 9 to lock the plunger in the position shown in Fig. 2. Locking pin 31 is-urged to a retracted positionby a compression spring 33 which acts between the shoulderformed by the reducedape'rture 32 and the head of locking pin 31. The outer, end of pin 31 in engagement with groove 13 of the slidable plunger. There is provided a hollow portion 35 within sections 3 and 4 having a reduced aperture 36 in one end thereof communicating with bore 29. Within sec-.

tion 2 of'the fuze body is a bore 37 of smaller diameter than hollow portion 35 and communicating therewith is an aperture 38 in cover plate 1. Slidably disposed with in aperture 36, hollow portion 35 and bore 37 is a rack 39 having teeth 41 some of whichare enlarged as at 42. A compression spring 43 is provided which acts between the shoulder formed by cover plate 1 surrounding aperture 38 and a tooth 41 and this spring urges rack 39 through aperture 36 thereby extending into engagement with locking pin 31 to retain this pin within groove 13 of the slidable plunger 9.

Within hollow portion 35 there is rotatably mounted .a gear 44 '(Fig. 6) the teeth of which mesh with teeth 41 on the rack member 39. This gear is made of a'material chosen so that the'weight of the gear is sufiicient to add enough inertia to the rack member to prevent complete withdrawal of the rack from engagement with the locking pin except under conditions of sustained set back force incurred only upon firing.

The operation of the device is as follows. Upon firing a projectile containing the disclosed fuze the parts I will be in the position shown in Fig. 2. The set back force due to inertia will cause rack member 39 to be withdrawn from engagement with locking pin 31 through aperture 36. In so doing the rack overcomes both the resistance ofi'eredby spring 43 and the inertia of gear 44. When the rack member is completely withdrawn through aperture 36, the enlarged teeth 42 engage the gear wheel causing the rack member to shift to the position shown in Fig. 5. It will be seen that after the rack member has been so shifted it is prevented from reentering aperture 36 both by the spring 43 which forces the rack member against the shoulder surrounding aperture 36 and by the engagement of gear 44 with the enlarged teeth. When the rack member is withdrawn from engagement with locking pin 31, spring 33 forces this pin to a retracted position out of engagement with slidable plunger 9.

Substantially simultaneously with retraction of this locking pin the gas generating device located in port 26 is actuated thereby generating pressure behind the slidable plunger 9. Upon creation of suflicientpressure plunger 9 is thrust forward thereby bending flange 11 inwardly. This thrust is imparted to rotor 16 through tooth 18 and the rotor rotates to the position shown in Fig. 4 in response thereto. The tooth engages the plunger for only approximately 30 of the total 80 movement of the rotor, the plunger imparting sufficient momentum to the rotor for rotation for the remaining 50.

the wall of the bore so as to force the rack member out of alignment with aperture 36 when the rack member is in a withdrawn position. In this form the gear 44 serves no other purpose than as an inertia element to add weight to the rack member and prevent premature withdrawal. In either embodiment it should be clear that integration of motion of the rack member on a succession of acci dental drops is impossible due to the fact that spring 43 returns the rack member'to its initial position after each vibration or accidentaldrop. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. r

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A locking means for a fuze comprising a body having a bore therein and an interconnecting aperture arranged transversely thereto, a spring pressed locking pin slidably mounted in said bore, an elongated rack member extending into engagement with said locking pin through said aperture and normally retaining said locking pin in locking position, a first group of teeth and an The rotor is stopped in the position of alignment of the detonator and the lead-in charge by the engagement of the stop pin 23 with the cut away portion 17 of the rotor. Spring 24 engages notch 25 to prevent counterclockwise movement of the rotor which is thereby effectivcly held in the armed position.

den deceleration incurred by an accidental drop will not cause complete withdrawal of the rack member.

Obviously many. modifications and variations of the present invention are possible in the. light of the above teachings. For example, the enlarged teeth 42 could be 1 replaced by teeth of normal size such as shown at 41 and a spring provided to set between rack member 39 and out of engagement with said enlarged group of teeth,

said rack member being withdrawn through said aperture in response to set back force to release the locking pin whereby withdrawal of said rack member positions said enlarged group of teeth to engage said geared inertia wheel thereby shifting said rack member out of alignment with the aperture.

2. A locking means for a projectile fuze comprising a toothed rack member pressed to a locking position by means of a spring and movable to a retracted position by the set back force incurred when the projectile is fired, and a geared inertia wheel initially meshing with a section of teeth on the rack member and proportioned to add sufficient weight to the locking means to prevent substantial movement of the rack member when the set back force is of less than predetermined duration, said rack member having a section of enlarged teeth out of engagement with the geared inertia wheel when the rack member is in a locking position and so positioned that when the rack member is retracted due to set back force said section of enlarged teeth engage said inertia wheel whereby the rack member is shifted out of the line of normal longitudinal movement ofthe rack member thereby preventing return of the rack member to locking position.

3. In a projectile fuze having a slidable pressure responsive member adapted to actuate a rotor for arming the fuze, a locking means for the slidable member comprising a pin in engagement with the slidable member and spring urged toward retracted position, an elongated toothed rack member disposed along the longitudinal axis ofthe projectile and normally spring pressed into engagement with said pin for maintaining the pin in the locking position, and a geared inertia wheel meshing with the teeth on the rack member whereby when the rack member is retracted by set back out of engagement with thepimthepin will be retracted and the pressure responsive member will be released. 1

4. In an arming device for a fuze having gas generating means and a rotor with a detonator adapted to be aligned with a primer and lead-in charge when armed and a pressure responsive plunger element having toothed engagement with the rotor, a locking means for the plunger element comprising, a locking pin spring urged to retracted position, a toothed rack member pressed into engagement with said pin by means of a spring to retain said pin in the locking position, a geared inertia wheel meshing with the teeth on the rack member and of suificient weight to prevent substantial movement of the rack member from a set back force of less than predetermined duration whereby upon initiation of the set back force due to firing the projectile, the rack member will be withdrawn in time delayed relation from engagement with the locking pin and said locking pin will be retracted releasing the pressure responsive plunger which is actuated by the gas generating means for movement to cause rotation of the rotor thereby aligning the detonator with the primer and lead-in charge.

5. A locking means for a projectile fuze comprising a fuze body having a bore therein and an interconnecting aperture arranged transversely thereto, a locking pin slidably mounted in said bore, spring means urging said pin to an unlocking position, a toothed rack member extending into engagement with said locking pin through said aperture and normally retaining said locking pin in a locking position, a geared inertia wheel rotatably mounted within said body and initially meshing with a section of teeth on said rack member, said rack member having an additional section of teeth of greater dedendum than the first mentioned section of teeth and so disposed along the rack member as to engage the geared wheel only when the rack member has been completely withdrawn through said aperture, said additional section of teeth when engaging said geared wheel causing said rack member to move angularly with respect to the normal path of movement of said rack member to a position out of alignment with said aperture to prevent the return of the rack member to the locking position.

6. In a projectile fuze having a slidable pressure responsive member adapted to actuate a rotor for arming the fuze, a locking means for the slidable member comprising a pin in engagement with the slidable member and spring urged toward a retracted position, an elongated member supported for longitudinal movement along a predetermined axis and normally spring pressed into engagement with said pin for maintaining the pin in the locking position, said elongated member being movable to a retracted position by set back force to thereby retract said pin and release said pressure responsive member, motive means mounted contiguous to said elongated member, said elongated member having a first body portion initially engaging said motive means when said elongated member maintains said pin in the locking position and an enlarged body portion positioned to engage said motive means when said elongated member is in the retracted position whereby said elongated member is displaced from said predetermined axis, and arresting means for preventing longitudinal movement of said elongated member when displaced from said predeter mined axis.

References Cited in the file of this patent UNITED STATES PATENTS 

